1. Field of the Invention
The present invention relates to a mobile communication system and, in particular, to a reliable group multicast transmission method and apparatus using a cell broadcasting technique in the mobile communication system.
2. Description of the Related Art
Mobile communication systems developed to provide the subscribers with voice communication services on the move. With the rapid advance of technologies, the mobile communication systems have evolved to support high speed data communication services as well as the standard voice communication services. However, the resource shortage and user requirement for higher speed data services spurs the evolution of the mobile communication system to more advanced system.
Meanwhile, there are a few methods for transmitting the same information to plural terminal users such as Cell Broadcast Service (CBS) and Multimedia Broadcast and Multicast Service (MBMS). The CBS is a technology of transmitting the same information to all terminals within a particular region or whole mobile communication network. The information transmitted through CBS includes emergency information for the natural disaster warning. The MBMS is a technology of transmitting the same information within a particular group.
However, the conventional CBS has a drawback in that the broadcast signal cannot be addressed to a specific group and its transmission reliability is not guaranteed. For example, the packet communication terminal may not receive the information transmitted through CBS.
Meanwhile, the MBMS is a packet-based technology capable of multicasting information to a particular group, the MBMS scheduling information is transmitted in unicast message such as SMS, resulting in low utilization efficiency.
There is therefore a need of a multicast method capable of transmitting specific information to a particular group while guaranteeing transmission reliability in radio communication system.